Please. Please. Advise. ASAP.

96 Imprezza SOHC EJ22.

New timing belt;  new spark plugs.

#2 spark plug has fired (175 psi).

1, 3 & 4 spark plugs haven't. (Zero psi)

Why??

OBD shows PO325 knock sensor error code

Never mind my two front teeth -- all I want for Christmas is to drive my car again.

Please. Please. Advise. ASAP.

 

Edited December 12, 20241 yr by JesusLady
Additional info

Did it run after the new timing belt? Was it running good before the timing belt was changed? If it was running before the timing belt change, I’m guessing that the belt was installed incorrectly and it bent a valve on each of those cylinders, thus no compression.

Of course, that could be a non-interference engine and in that case, I have no idea.

Zero psi anywhere sounds bad.  You need to test and make sure you have compression at all cyls.

The belt has to come off again.  Turn each camshaft by hand until they're unloaded so the valves are closed.  With the spark plugs out, turn the crankshaft by hand to confirm it's not catching on anything.  If all is well, test the compression without the timing belt installed and confirm you're getting pressure.

6 hours ago, nvu said:

If all is well, test the compression without the timing belt installed and confirm you're getting pressure.

This won’t give accurate readings as the cylinder is not able to suck air in freely to compress as it would in operation. It would only show that cylinders don’t have leaking valves, even then, depending on how the engine stopped with piston positions in each cylinder, some cylinders might not show up anything. 

To be as accurate as possible you’d need to ensure the cylinder being tested is at bottom dead centre. This would give the best possible compression test with both valve sets closed. 

Cheers 

Bennie

Edited December 13, 20241 yr by el_freddo

Good point el_freddo, the results won't be accurate.  My reasoning would be to rule out any seriously broken parts.  With only the compression tester in one hole and the no spark plug in the others.  The main idea is to verify each cylinder still has any compression.  If one cylinder has bent valves or something broken, the starter wouldn't have much resistance and spin freely.  If there's really a 0psi at this point, something is majorly bent, not tightened down, or broken.

Edited December 13, 20241 yr by nvu

Correct Timing belt installation.  

Make sure it turns over by hand freely.  Pull the valve covers and watch the cams/rocker arms.  

Does it feel like there is compression on each cylinder as you turn it over by hand?

If so throttle wide open as you crank it over with the throttle wide open to check the compression on each cylinder.